Related Experiment Video
Updated: Jun 10, 2026
11:24
Measuring DNA Damage and Repair in Mouse Splenocytes After Chronic In Vivo Exposure to Very Low Doses of Beta- and Gamma-Radiation
Published on: July 3, 2015
Radiation Induced Bystander Effect in vivo.
1Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, USA.
Acta Medica Nagasakiensia
|July 17, 2010
Summary
The radiation-induced bystander effect occurs in cells not directly hit by radiation. This review summarizes evidence for this effect in vivo, highlighting conserved mechanisms but noting limited mechanistic studies.
Area of Science:
- Radiobiology
- Cellular and Molecular Biology
Background:
- The radiation-induced bystander effect describes biological responses in non-irradiated cells adjacent to irradiated cells.
- While well-characterized in vitro, in vivo evidence and mechanisms remain less understood.
Purpose of the Study:
- To review and summarize existing evidence for the radiation-induced bystander effect in various in vivo models.
- To highlight observed biological endpoints and discuss the conservation and variability of the effect in vivo.
Main Methods:
- Literature review of studies investigating radiation-induced bystander effects in vivo.
- Analysis of data from various model organisms including rodents, fish, and plants.
Main Results:
- Evidence for the radiation-induced bystander effect is present in diverse in vivo systems.
- Observed endpoints include epigenetic changes, DNA damage, miRNA alterations, apoptosis, cell proliferation changes, gene expression modulation, and tumorigenesis in non-targeted cells.
- The bystander effect is evolutionarily conserved in rodents, but responses vary by gender, tissue, and strain.
Conclusions:
- The radiation-induced bystander effect is demonstrable in vivo across multiple species.
- Despite conservation, the underlying mechanisms in vivo require further extensive investigation.
Related Concept Videos
02:59Biological Effects of Radiation
All radioactive nuclides emit high-energy particles or electromagnetic waves. When this radiation encounters living cells, it can cause heating, break chemical bonds, or ionize molecules. The most serious biological damage results when these radioactive emissions fragment or ionize molecules. For example, α and β particles emitted from nuclear decay reactions possess much higher energies than ordinary chemical bond energies. When these particles strike and penetrate matter, they produce ions...
01:35Mutations
Mutations are changes in the sequence of DNA. These changes can occur spontaneously or they can be induced by exposure to environmental factors. Mutations can be characterized in a number of different ways: whether and how they alter the amino acid sequence of the protein, whether they occur over a small or large area of DNA, and whether they occur in somatic cells or germline cells.
Chromosomal Alterations Are Large-Scale Mutations
While point mutations are changes in a single nucleotide in...
Chromosomal Alterations Are Large-Scale Mutations
While point mutations are changes in a single nucleotide in...
01:18Other Unique Bacteria
Magnetic bacteria exhibit a directed movement called magnetotaxis, driven by structures called magnetosomes. These magnetosomes consist of chains of magnetic particles made of either magnetite (Fe₃O₄) or greigite (Fe₃S₄) and are organized in a linear conformation by a protein scaffold within invaginations of the cell membrane. The bacteria align along the north–south magnetic field lines, much like a compass needle. They are typically microaerophilic or anaerobic and are commonly found near the...
02:09Bystander Effect
The discussion of bullying highlights the problem of witnesses not intervening to help a victim. This is a common occurrence, as the following well-publicized event demonstrates. In 1964, in Queens, New York, a 19-year-old woman named Kitty Genovese was attacked by a person with a knife near the back entrance to her apartment building and again in the hallway inside her apartment building. When the attack occurred, she screamed for help numerous times and eventually died from her stab wounds.
01:05Absorption of Radiation
The rate of heat transfer by emitted radiation is described by the Stefan-Boltzmann law of radiation:
01:38Nucleotide Excision Repair
DNA Distortion and Damage
Cells are regularly exposed to mutagens—factors in the environment that can damage DNA and generate mutations. UV radiation is one of the most common mutagens and is estimated to introduce a significant number of changes in DNA. These include bends or kinks in the structure, which can block DNA replication or transcription. If these errors are not fixed, the damage can cause mutations, which in turn can result in cancer or disease depending on which sequences are...
Cells are regularly exposed to mutagens—factors in the environment that can damage DNA and generate mutations. UV radiation is one of the most common mutagens and is estimated to introduce a significant number of changes in DNA. These include bends or kinks in the structure, which can block DNA replication or transcription. If these errors are not fixed, the damage can cause mutations, which in turn can result in cancer or disease depending on which sequences are...